This type of protective hoods have the advantage that the protective hood is installed and removed on the tool machine without the use of tools. In addition, the protective hood in the secured condition, depending on need, can be brought, relative to the tool machine, also without the use of tools from one locked position into another.
CH 682 732 A5 discloses a protective hood arrangement, where the protective hood has an annular holding part, on which two brackets project inwardly. At one fastening flange of the tool machine, an annular receiving groove formed by two access recesses towards the free end of the fastening flange extend, whose cross-section and arrangement correspond to the form and arrangement of the brackets on the protective hood. When installing the protective hood, the brackets are urged over the access recesses into the receiving groove and then by rotating, together with the later brought into a bayonet-type engagement. In addition, on an underside of the tool machine, around the fastening flange, depressions are formed into which locking cams of the protective hood can interlock and which project axially on a free end part of an annular holding part.
The drawback in the prior art protective hood arrangement is that the features for the optional fixing of the protective hood in different locking positions are relatively expensive and consequently result in high costs of manufacture. In addition, the receiving groove in cross-section must be relatively precisely matched to the thickness of the brackets, in order to prevent a disturbing rattling during operation. At the same time, this precise matching of the receiving groove to the dimensions of the brackets results in a slight sticking, particularly when the brackets are slightly bent. This can result in a misalignment of the protective hood into a new locking position or can result in substantial problems at the time of their installation or dismantling.